fix: retry transient RSS fetch failures with backoff

Co-authored-by: Cursor <cursoragent@cursor.com>

.env.example

@@ -86,6 +86,8 @@ DAILY_AI_NEWS_PER_CATEGORY=5
 # DAILY_AGENT_CN_NEWS_POOL=30
 
 # RSS 源：编辑 config/feeds.yaml（intl / cn）；缺失时回退内置默认
+# 单源失败重试次数（默认 3，含首次请求）
+# DAILY_RSS_RETRY=3
 # 内容过滤：config/sensitive_words.yaml + DAILY_CONTENT_FILTER=1
 # DAILY_CONTENT_FILTER=0
 

daily/news/fetch.py

@@ -289,8 +289,10 @@ def _fetch_one(
     category: NewsCategory,
     feed: NewsFeed,
 ) -> tuple[list[dict[str, Any]], bool]:
+    max_attempts = max(1, env_int("DAILY_RSS_RETRY", 3))
     last_exc: Exception | None = None
     for url in _reddit_fetch_urls(feed.url):
+        for attempt in range(max_attempts):
             try:
                 headers = _request_headers(dict(client.headers), url)
                 resp = client.get(url, headers=headers)
@@ -299,7 +301,10 @@ def _fetch_one(
                 return _filter_ai_entries(entries, ai_filter=feed.ai_filter), True
             except Exception as exc:
                 last_exc = exc
+                if attempt + 1 < max_attempts:
+                    time.sleep(min(2.0 * (attempt + 1), 5.0))
                     continue
+                break
     logger.warning("RSS fetch failed [%s] %s: %s", feed.name, feed.url, last_exc)
     return [], False
 

tests/test_rss_parse.py

@@ -29,6 +29,42 @@ def test_rss_user_agent_avoids_bot_blocked_feeds():
     assert "daily-robots" not in RSS_USER_AGENT
 
 
+def test_fetch_one_retries_transient_errors(monkeypatch):
+    import httpx
+
+    from daily.news.feeds import NEWS_CATEGORIES
+    from daily.news import fetch as news_fetch
+
+    monkeypatch.setenv("DAILY_RSS_RETRY", "2")
+    monkeypatch.setattr(news_fetch.time, "sleep", lambda _: None)
+
+    category = NEWS_CATEGORIES[0]
+    feed = category.feeds[0]
+    calls = {"n": 0}
+
+    class FakeResponse:
+        def raise_for_status(self):
+            return None
+
+        @property
+        def text(self):
+            return (FIXTURES / "sample-rss.xml").read_text(encoding="utf-8")
+
+    class FakeClient:
+        headers = {"User-Agent": "test"}
+
+        def get(self, url, headers=None):
+            calls["n"] += 1
+            if calls["n"] < 2:
+                raise httpx.RemoteProtocolError("Server disconnected")
+            return FakeResponse()
+
+    entries, ok = news_fetch._fetch_one(FakeClient(), category, feed)
+    assert ok is True
+    assert len(entries) == 1
+    assert calls["n"] == 2
+
+
 def test_fetch_ai_news_offline(monkeypatch):
     from daily.news import fetch as news_fetch